1. Field Of The Invention
The present invention relates to tape recorders. More specifically, the present invention is directed to a tape reel brake for tape recorders.
2. Description Of The Prior Art
In tape recorders using a pair of tape reels to store and to supply a recording tape therebetween, it is desirable to provide a differential braking action on the tape reels. Thus, the tape reel supplying the tape to the tape drive system should have a greater braking force applied to it than the tape reel accepting tape from the tape transport system in order to maintain tape tension and prevent loose loops of tape particularly when the tape is not being driven by a tape capstan. Since a recorder is a bi-directional device, i.e., the tape can be driven in either direction by the tape capstan, each tape reel should be capable of two levels of braking, i.e., a first level when the tape reel is supplying tape and a second braking level when the tape reel is accepting tape. It is further desirable that the braking effect and the selection of braking force levels be completely automatic in operation during a switching of the tape travel direction. The use of a simple slipping clutch to provide a braking action determined by spring pressure on the clutch is well-known in the art as shown in U.S. Pat. No. 2,643,531. On the other hand, there have been prior art attempts to provide changes in the braking force on tape reels dependent on the direction of travel of the recording tape as shown in U.S. Pat. Nos. 3,452,840; 3,670,992; 3,690,588 and 3,869,100. All of these prior art devices use complicated mechanical structures for achieving such a bi-directional reel braking effect and, consequently, are unable to provide a cost-effective structure on a tape recorder.